Snow plow structure with means to exert down pressure on slade



March 30, 1965 J. w. RENAHAN 3,175,313

SNOW PLOW STRUCTURE WITH MEANS T0 EXERT DOWN PRESSURE ON SLAIDE FiledJan. 16, 1963 INV NTOR aflmda a PATENT AGENT United States Patent3,175,313 SNOW PLOW STRUCTURE WITH MEANE T8 EXERT DOWN PRESSURE 0N SLADEJohn W. Renahan, Willowdale, Ontario, Canada, assignor to TurnhullElevator Limited, Toronto, Ontario, Canada Filed Jan. 16, 1963, Ser. No.251,853 2 Claims. (Cl. 37-42) This invention relates to snow plowstructures.

It is usual to load the blade of a snow plow to an extent sufiicientthat the blade will perform a good scraping or cleaning jobv In somecases, a very heavy blade structure is provided whereby there issufficient inherent weight in the structure itself. Obviously, this isnot an economical arrangement. A more usual and conventional form ofstructure comprises the provision of a light blade structure withhydraulic means exerting downward pressure thereon. Since the hydraulicmeans is under the control of an operator and since it is quitedifiicult to determine a satisfactory degree of pressure to be applied,this type of equipment frequently results in excessive pressure on theroad surface with a consequent damaging effect on such surface.Moreover, as the blade wears down, the hydraulic pressure must beperiodically adjusted by the operator, and again it is quite ditficultto achieve the desired fine degree of adjustment.

It is an object of this invention to provide a snow plow structurewherein a predetermined load is applied to the blade from the carryingvehicle.

Another object is to provide a snow plow structure wherein apredetermined load is applied to the blade whereby such loadautomatically compensates for wear of the blade.

Another object is to provide a snow plow structure wherein any desireddegree of preloading may be applied to the blade.

Another object is to provide a simple, relatively inexpensive snow plowstructure of reduced weight wherein the downward force thereof comprisesa combination of the weight of the blade structure and a preloadedspring means.

The invention resides in a snow plow structure comprising, incombination with a generally horizontal vehicle frame, a rigid bladesupporting frame pivotally carried by said vehicle frame, a blade fixedto said supporting frame, and resilient pressure applying means actingon said blade supporting frame to apply downwardly directed resilientpressure on said blade.

The invention will be described with reference to the accompanyingdrawing, in which:

FIGURE 1 is a perspective view of a snow plow structure in accordancewith the invention,

FIGURE 2 is a sectional view on line 22 of FIGURE 1, and

FIGURE 3 is a side elevation of a modified form of snow plow structure.

Referring to FIGURES 1 and 2, 1 is a portion of a carrying vehiclehaving longitudinal beams 2 and a transverse beam 3.

The plow structure comprises an upright plate 4 fixed to the transversebeam 3. A pair of blade-carrying arms 5 each have one end thereofpivotally mounted as by a pin 6 in brackets 7 fixed to the plate 4. Ablade 8 is fixed as by welding to the other ends of the arms 5.

A torsion spring 9 is coiled about each pin 6 and has one end portion 10fixed, as by welding, to plate 4 and another end portion 11 fixed, as bywelding to an arm 5. Each end portion 11 is torsionally loaded in adownward direction. Thus, such end portion 11 may have a normal unloadedposition indicated at 11a in dotted lines.

3,175,313 Patented Mar. 30, 1965 Means for raising and lowering theblade may comprise a pair of arms 12 pivotally mounted on plate 4 abovearms 5 and carrying a bracket 13 having chains 13a connecting thebracket to arms 5. A hydraulic cylinder 14 has a connecting bar 15pivotally mounted at 16 to a bracket 17 fixed to plate 4- and aconencting rod 18 pivoted at 19 to bracket 13.

It will be apparent that the springs 9 and the torsional loading on endportions 11 may be chosen to provide any desired degree of loading onthe blade 8.

It will also be understood that in the down or operating position of theblade, the hydraulic cylinder 14 is at the end of its downward strokeand applies no lifting force on the blade.

Referring to FIGURE 3, the blade 20 is fixed to a mounting plate 21 andis pivotally carried by the vehicle frame 22. by means of pivot pin 23and brackets 24 and 25. Resilient pressure is applied to the blade in adownward direction by means of one or more tension springs 26 one end ofwhich is connected to plate 2.1 and the other end of which is connectedto the vehicle frame. A hydraulic cylinder 27 may be provided forraising and lowering the blade.

I claim:

1. A snow plow comprising a mobile frame, a substantially verticallydisposed plate rigidly affixed to said frame and extending transverselyof the path of movement thereof, a transversely extending blade disposedforwardly of the frame and generally in parallel relation thereto, saidblade having an arcuate curvature from top to bottom to facilitateplowing of snow, a pair of substantially parallel and horizontallyextending arms rigidly aflixed to the rear convex surface of the blade,means pivotally connecting the ends of the arms remote from the blade tosaid plate for pivotal movement of the blade about substantially ahorizontal axis, said means pivoting the arms to the plate including a.pair of flanges rigidly secured to said plate adjacent each outer bottomcorner thereof receiving the ends of the arms respectively therebetween,a pivot pin extending through said flanges and through the inner end ofeach arm, each pivot pin extending beyond the flanges toward the outeredge of the plate, a torsion coil spring mounted on said projectingpivot pin and having a laterally extending end engaging with the plateand a laterally extending end connected with the arm in spaced relationto the pivot pin to bias said arms and blade in a downward direction, apair of bars disposed in overlying relation to said arms and disposed ina horizontal plane generally parallel to the plane of the arms, saidbars converging forwardly, a transverse member rigidly interconnectingthe outer adjacent ends of said bars, means pivotally mounting the innerends of the bars to the upper outer corners of said plate for pivotalmovement about a horizontal axis parallel to the horizontal axis ofmovement of said pair of arms, a flexible member connected to each endof said transverse member at the forward ends of said bars and extendingdownwardly therefrom, said flexible members being in the form of chainshaving their lower ends attached to said arms at a point adjacent to butspaced from the blade, the length of said transverse member being lessthan the distance between said arms whereby the chains extend downwardlyin a diverging manner, a hydraulic piston and cylinder assembly havingone end pivotally connected to the lower central edge of said plate, theother end of the assembly being pivotally connected to the adjacent endsof said bars and said transverse member at the center thereof wherebyextension of said hydraulic piston and cylinder assembly will ele vatethe blade to an inoperative lifted position and contraction of thepiston and cylinder assembly will enable the blade to be positioned inan operative position for plowing snow.

2. A snow plow comprising a mobile frame, a mounting plate underlyingsaid frame and projecting longitudinally therefrom, means pivotallymounting an intermediate portion of said plate on said frame for pivotalmovement about a transverse horizontal axis, an arcuate plow bladerigidly attached to said plate at the end thereofprojecting from theframe, a spring interconnecting the plate and said frame inlongitudinally spaced relation to the transverse pivotal axis of thepoint of connection of the plate to the frame for biasing the end of theplate having the blade thereon in a downward direction, and a hydraulicpiston and cylinder assembly 15 References Cited by the Examiner UNITEDSTATES PATENTS 52,028 1/66 Carncross 3730 X 1,108,263 8/14 Smith 1727051,678,113 7/28 Gustafson 3742 X 1,698,809 1/29 Angell 3742 1,720,4907/29 Koller 17270 5 1,973,830 9/34 Tomkin 371'80 2,091,343 8/37 Soule37-42 3,055,126 9/62 Emhof 3742 FOREIGN PATENTS 11/57 Belgium. 12/43Netherlands.

OTHER REFERENCES 20 BENJAMIN HERSH, Primary Examiner.

2. A SNOW PLOW COMPRISING A MOBILE FRAME, A MOUNTING PLATE UNDERLYINGSAID FRAME AND PROJECTING LONGITUNIDALLY THEREFROM, MEANS PIVOTALLYMOUNTING AN INTERMEDIATE PORTION OF SAID PLATE ON SAID FRAME FOR PIVOTALMOVEMENT ABOUT A TRANSVERSE HORIZONTAL AXIS, AN ARCUATE PLOW BLADERIGIDLY ATTACHED TO SAID PLATE AT THE END THEREOF PROJECTING FROM THEFRAME, A SPRING INTERCONNECTING THE PLATE AND SAID FRAME FOR BIASING THEEND RELATION TO THE TRANSVERSE PIVOTAL AXIS OF THE POINT OF CONNECTIONOF THE PLATE TO THE FRAME FOR BIASING THE END OF THE PLATE HAVING THEBLADE THEREON IN A DOWNWARD DIRECTION, AND A HYDRAULIC PISTON ANDCYLINDER ASSEMBLY INTERCONNECTING THE PLATE AND THE FRAME INTERMEDIATETHE SPRING AND THE PIVOTAL CONNECTION BETWEEN THE PLATE AND FRAME FORLIFTING THE BLADE WHEN THE PISTON AND CYLINDER ASSEMBLY IS EXTENDED THUSOVERCOMING THE RESILIENT EFFECT OF THE SPRING.